Yes there are quite a few Miatas that have had the "treatment" namely superchargers, turbo chargers, coilovers, etc etc etc and are for sale . Sounds like a good situation for you to acquire one. If you don't like the add ons you can sell them. Myself I just want stock. If the suspension is too hard that is not good for me but each one to their own
Miatas have a world of their own just like Porsche. Congrats on your purchase.